He was the commander of the NASA's Apollo 11 space flight on July 20, 1969.
Armstrong's second and last spaceflight was as mission commander of the Apollo 11 moon landing mission on July 20, 1969.
- On this mission, Armstrong and Buzz Aldrin descended to the lunar surface and spent 2½ hours exploring while Michael Collins remained in orbit in the Command Module.
- The objective of Apollo 11 was to land safely rather than to touch down with precision on a particular spot.
- The first words Armstrong intentionally spoke to Mission Control and the world from the lunar surface were, "Houston, Tranquility Base here. The Eagle has landed."
- Armstrong set his left boot on the Moon's surface at 2:56 UTC July 21, 1969, then spoke the famous words "That's one small step for [a] man, one giant leap for mankind."
- There was a controversy over whether Armstrong said "a" before the word "man" or not and several researches were made over this.
- About 20 minutes after the first step, Buzz Aldrin joined Armstrong on the surface and became the second human to set foot on the Moon, and the duo began their tasks of investigating how easily a person could operate on the lunar surface.
- Early on, they unveiled a plaque commemorating their flight, and also planted the flag of the United States.
- Shortly after their flag planting, the then President of USA Richard Nixon spoke to them by a telephone call from his office.
- In the entire Apollo 11 photographic record, there are only five images of Armstrong partly shown or reflected.
- The mission was planned to the minute, with the majority of photographic tasks to be performed by Armstrong with a single Hasselblad camera.
- After helping to set up the Early Apollo Scientific Experiment Package, Armstrong went for a walk to what is now known as East Crater, 65 yards (59 m) east of the LM, the greatest distance traveled from the LM on the mission.
- Armstrong's final task was to leave a small package of memorial items to deceased Soviet cosmonauts Yuri Gagarin and Vladimir Komarov, and Apollo 1 astronauts Gus Grissom, Ed White and Roger Chaffee.
- The time spent on EVA during Apollo 11 was about two and a half hours, the shortest of any of the six Apollo lunar landing missions.